How to - What is the Best Way to a change the Transaxle Fluid?

[David T]

Beat the socket on ALL the way with a hammer. Use a breaker bar and a cheater pipe and try again. If you can't get it you can drill it out. Heat isn't as effective because it is a taper thread. Welding a nut on is possible and can work if you have access to a welder. You can't really heat it up enough because you do still have oil inside. If you get a new plug try to get a magnetic one. Use teflon tape so this doesn't happen again.

[Ras12]

Ok so with a little PB Blaster and Heat I was able to get the drain plug out. The transaxle case was full but I don’t think this is the correct color of the fluid. Is it supposed to be this dark drown? And it smells like burnt oil!! Also how do I “flush” the transfer case so it is clean when I finally fill it? Thanks.

[Ron]

Looks like non-synthetic gear oil (which it should be, imho). It is supposed to be noticeably thicker than engine oil. Always smells bad, including when new.

If there were no signs of moisture (milky appearing substance/gel), sludge or metal particles in it, especially in the first to come out, just refill it; For GP/SOP, drive it until the case gets hot then drain & fill again.
If it was extremely contaminated, there are solvents and recirculating tools on the market you can use. (Doesn't seem to be the case here).

[Mark D]

That looks pretty normal in color to me as well.

Gear oil always smells horrible. I think it has something to do with the additives they put in for wear protection. Sulfur maybe?

I have the pleasure of smelling it every time I open the trunk in my daily driver. About 9 years ago when I last changed the gear oil in the DeLorean I had drained it into a 5 gal bucket along with the oil from a recent engine oil change. I put the bucket in the trunk of my car and headed to the recycling center drop off.

On the way there I went over some railroad tracks and the bucket toppled over and the cover popped off. That nasty smelling oil soaked through all the trunk carpets and filled up the spare tire well. It also wicked between all the gaps in the sheet metal making it nearly impossible to clean out. Every once in a while I still go back there with some brake cleaner and paper towels and can still pick up oil residue.

On the plus side, there's absolutely no rust back there

[Nicholas R]

That looks normal. Gearbox oil has a lot of sulfer in it; its the main thing that gives it the distinct smell. It smells pretty bad, but I find you go nose blind to it after a bit. My wife on the other hand wont even come into the garage if I'm doing anything with gearbox oil.

[02fanatic]

I think the trans plugs are different than the engine oil drain plug (at least on a manual?). This is what the trans fill plug looks like:
Attachment 63251

Does anyone know what the specs are for the threads on the 5-speed transmission drain plug?

[Josh]

Does anyone know what the specs are for the threads on the 5-speed transmission drain plug?

drain and fill are 1/4" NPT

[JAZ_DMC]

drain and fill are 1/4" NPT

Drain and fill are not 1/4" NPT – both are actually 3/8" NPT. 3/8" 18 NPT to be exact (for anyone who may be looking for the correct size tap).

02fanatic (dad) and I had a tough time finding a clear answer for this question online, so I thought I'd add some keywords here for others who may be Googling for this answer in the future.

DeLorean - transmission - gearbox - 5-speed - drain plug size - thread size - stripped - cross thread - DMC - national pipe thread - taper - tapered - chase threads

[JSzabo]

Is this the type of Gear Oil I need for my manual transmission?

https://www.amazon.com/Lucas-Oil-LUC...0&sr=1-28&th=1

Or should I just go with the Super Tech (Walmart) 80W-90?

[Josh]

Drain and fill are not 1/4" NPT – both are actually 3/8" NPT. 3/8" 18 NPT to be exact (for anyone who may be looking for the correct size tap).

02fanatic (dad) and I had a tough time finding a clear answer for this question online, so I thought I'd add some keywords here for others who may be Googling for this answer in the future.

DeLorean - transmission - gearbox - 5-speed - drain plug size - thread size - stripped - cross thread - DMC - national pipe thread - taper - tapered - chase threads

You made me go out in the cold and measure my spare transaxle in the shed! It is indeed 3/8" NPT